<?php
/*******************************************************************************
** Title.........: cron class: **
** Summary.......: determine if an action is due based on two timestamps **
** and a specifier in the classic crontab format **
** Version.......: 0.2.8 **
** Author........: Klaus P. Pieper <klaus_p.pieper@t-online.de> **
** Project home..: http://klaus_p.pieper.bei.t-online.de/ **
** Filename......: class.cron.inc **
** Copyright(C)..: 2002 Klaus P. Pieper **
** Last changed..: 12 August 2002 **
** License.......: GNU Lesser General Public License (see below) **
** **
** This library is free software; you can redistribute it and/or **
** modify it under the terms of the GNU Lesser General Public **
** License as published by the Free Software Foundation; either **
** version 2.1 of the License, or (at your option) any later version. **
** **
** This library is distributed in the hope that it will be useful, **
** but WITHOUT ANY WARRANTY; without even the implied warranty of **
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU **
** Lesser General Public License for more details. **
**
** You should have received a copy of the GNU Lesser General Public **
** License along with this library; if not, write to the Free Software **
** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA **
*******************************************************************************/
/*******************************************************************************
** Version history:
** 0.2.7: 08-Aug-2002: yet another minor bug fix in the decision logic
** 0.2.7: 08-Aug-2002: another minor bug fix in the decision logic
** 0.2.6: 29-Jul-2002: minor bug fix in the decision logic
** 0.2.5: 26-Jul-2002: decision logic in procedure due completely
** re-written, carry over principle omitted
** 0.2.4: 25-Jul-2002: more minor bug in carry over procedure
** 0.2.3: 25-Jul-2002: minor bug fixes,
** - specifying weekdays
** - carry over flag added
** - arCFOffset added for the carry over function
** 0.2.2: 18-Jul-2002: added FALSE return for $tLast == NULL
** 0.2.1: 15-Jul-2002: first published version
*******************************************************************************/
class cron {
// this is the heart of the class
// $tLast: last time at which the command was completed
// $tNow: the reference time, usually the current time stamp
// $sSpec: the specifier in the usual crontab format
// returns TRUE if a timestamp exists between $tLast and $tNow
// fulfilling the $sSpec criteria.
// returns FALSE otherwise
function due($tLast, $tNow, $sSpec)
{
// this array describes the classic crontab format
// for internal use the elements are listed in reverse order
$arSeg = array("wday", "mon",
"mday", "hours",
"minutes");
// alternate crontab format includes year
// this format is internally not (yet) supported!!!
/* $arSeg = array("year", "wday",
"mon", "mday",
"hours", "minutes");
*/
// this array contains the offset in case for the carry over status
// see below for the determination of the carry over status
$arPeriod = array("wday" => 7,
"mon" => 12,
"mday" =>
array(31, 28, 31, 30, 31, 30,
31, 31, 30, 31, 30, 31),
"hours" => 24,
"minutes" => 60);
$arTime = array("wday" => 604800, // 7 * 24 * 60 * 60
"mon" => 31536000, // 365 * 24 * 60 * 60
"mday" =>
array(31 * 86400, // 31 * 24 * 60 * 60
28 * 86400,
31 * 86400,
30 * 86400,
31 * 86400,
30 * 86400,
31 * 86400,
31 * 86400,
30 * 86400,
31 * 86400,
30 * 86400,
31 * 86400),
"hours" => 86400, // 24 * 60 * 60
"minutes" => 3600); // 60 * 60
$iSeg = 0; // segment index
$iCmpVal = 0; // compare value
// these lines added in 0.2.5
$bStatus = FALSE; // procedure status
$iPFaktor = 0; // period factor
$iTFaktor = 0; // time factor
if ($tNow == NULL) $tNow = time();
// this line added in version 0.2.2
if ($tLast == NULL) return FALSE;
// convert strings to time
if (is_string($tLast)) $tLast = strtotime($tLast);
if (is_string($tNow)) $tNow = strtotime($tNow);
if ($tNow < $tLast) return FALSE;
// convert time variables to arrays
$arLast = getdate($tLast);
$arNow = getdate($tNow);
$arSpec = array_reverse(explode(" ", $sSpec));
// walk through segments of crontab specifier
for ($iSeg = 0; $iSeg < count($arSeg); $iSeg ++) {
// obtain segment key
$sSeg = $arSeg[$iSeg];
// does specifier segment contain '*'?
if (strstr($arSpec[$iSeg], "*") != FALSE) {
// week days need special treatment
if ($sSeg == "wday") $iCmpVal = $arLast[$sSeg];
// use same segment of time reference
else $iCmpVal = $arNow[$sSeg];
// specifier segment contains specific criteria
} else {
// get reference value
$iCmpVal = cron::_nextLowerVal($arSpec[$iSeg], $arNow[$sSeg]);
} /* endif */
// this section completely changed in 0.2.5
// obtain period factor
$iPFactor = $arPeriod[$sSeg];
// numbers of days per month are always different ...
if ($sSeg == "mday")
@$iPFactor = $iPFactor[$arLast["mon"]];
// obtain period time factor
$iTFactor = $arTime[$sSeg];
// numbers of days per month are always different ...
if ($sSeg == "mday")
@$iTFactor = $iTFactor[$arLast["mon"]];
// this is the decisive part of the function:
if ($arLast[$sSeg] < $iCmpVal &&
$iCmpVal <= $arNow[$sSeg])
{ $bStatus = TRUE; }
if (strstr($arSpec[$iSeg], "*") == FALSE) {
// next two lines changed in 0.2.7
if ((($bStatus == TRUE && $arNow[$sSeg] == $arLast[$sSeg]) ||
$arNow[$sSeg] < $arLast[$sSeg]) &&
$arLast[$sSeg] < $iCmpVal + $iPFactor &&
$iCmpVal + $iPFactor <= $arNow[$sSeg] + $iPFactor &&
$iCmpVal >= 0)
{ $bStatus = TRUE; }
else if ($tNow > $tLast + $iTFactor)
{ $bStatus = TRUE; }
// note that this condition causes a premature return:
else if ($arLast[$sSeg] > $iCmpVal)
{ return FALSE; }
else if ($iCmpVal < $arNow[$sSeg] && $iCmpVal == $arLast[$sSeg] )
{ return FALSE; }
} /* endif */
// end of section
} /* endfor */
return $bStatus;
}
// this function determines the highest number specified in the
// crontab segment but smaller than the reference
// $sSpec: segment of crontab specifier
// $iRef: the reference number
// returns the number as described above, -1 if no number was found
function _nextLowerVal($sSpec, $iRef)
{
$arSpec1 = explode(",", $sSpec); // divide segment into details
$arInt = array(); // array of potential integers
$arSpec2 = array(); // array of details if
// specified as range
$i = 0;
$sEl = "";
// walk through list of details
foreach($arSpec1 as $sEl) {
// specified as range?
if(strchr($sEl, "-") != FALSE) {
// split again
$arSpec2 = explode("-", $sEl);
// add all numbers within range to list of integers
for ($i = $arSpec2[0]; $i <= $arSpec2[1]; $i ++)
array_push($arInt, $i);
} else { // not a range, add directly to list of integers
array_push($arInt, $sEl);
} /* endif */
} /* endfor */
// sort reverse, highest number is now 1st element
rsort($arInt);
// walk backwards through list
foreach($arInt as $iEl) {
// if element is smaller than reference, return element
if ($iEl <= $iRef) return $iEl;
} /* endfor */
// no element found
return -1;
}
} /* end of class definition */
?>